The present invention relates generally to a shielding member and, more particularly, to a radio frequency and electromagnetic interference shielding member for an electrical connector.
While the present invention will be described primarily herein as being a shielding member, as will be seen later in this description, the shielding member may be utilized as a spring contacting member for conducting electrical current or for grounding.
The use of shielding in electrical connectors to eliminate unwanted radio frequency and electromagnetic signals (RFI/EMI) and electromagnetic pulses (EMP) from interfering with signals being carried by contacts in connectors is well known. U.S. Pat. Nos. 3,521,222; 3,678,445 and 4,106,839 disclose annular shields formed of sheet metal with spaced resilient fingers extending in one longitudinal direction and formed to provide a spring connection between the mating halves of an electrical connector. The spring fingers of each such shield are spaced circumferentially from each other to provide open gaps so that substantial elimination of unwanted radio frequency and electromagnetic interference is not achieved. Another electrical connector shield which is well known in the art is formed from sheet metal and provided with alternating slots which open at opposite edges of the shield. The shield is expanded over the plug connector member and slightly compressed when the mating halves of the connector are inter-engaged. However, because the slots in the shield are open before the shield is mounted over the plug connector member, they remain open even after the connector halves are inter-engaged to compress the shield, thus leaving gaps which result in RFI, EMI and EMP leakage.
U.S. Pat. No. 3,835,443 discloses an electrical connector shield comprising a helically coiled conductive spring which is interposed between facing surfaces on the mating halves of a connector. The spring is coiled in such a manner that the convolutions thereof are slanted at an oblique angle to the center axis of the connector members. When the connector members are mated, the spring is axially flattened to minimize the gaps therebetween. However, as with the other prior art connectors discussed above, open gaps or windows still remain when the connector halves are fully mated.
A high current transfer device is also known in the art which comprises a metal band formed with transverse slots therein which are spaced from both edges of the strip. The strips of material between the slots are bent at an angle to form a louver arrangement. The louvered strips deflect when the band is compressed but it does not appear that the slots therebetween completely close.
It is the object of the present invention to provide an RFI, EMI and/or EMP shield, or contacting spring device, which provides a substantially continuous metal shield between the mating connector members thereby providing maximum attenuation of interfering signals, or maximum conductivity if functioning as a contacting device.